Drivetrain

Contributors:

The drivetrain was the first portion of the robot to be completed. Much of the drivetrain team was inexperienced with precision fabrication, and the students with robotics experience were unfamiliar with the challenges of building at this scale. Completion of the drivetrain mechanism however pioneered construction techniques that maximized the resources available to the team, and provided valuable design and project management skills that were crucial for later mechanical projects.

Many of the first drive train meetings involved brainstorming sessions that tended towards complicated, impractical, and expensive designs. Elaborate suspension mechanism, complicated arrangements of omni-wheels, and even gyroscopic balance on a single spherical castor where considered. Eventually we decided that one design principle would drive our first iteration: minimum viable product (MVP). Our main task was to create a functional drivetrain – not a perfect one. Once this principle guided us, the team progressed much more rapidly. Since creating a MVP could be done quite easily by just buying a commercial robotic drivetrain that met our requirements we then added secondary design principles:

Modularity – Any design change should require as little re manufacture and redesign as possible.

Cost - Even if the funds are available, we should always look for a route that can meet our requirements while using less team resources.

Speed – Whenever possible, we should manufacture parts using readily available resources. Also the manufacture process should be streamlined to prevent wasting team member's time on unnecessary tasks when there is a quicker solution.

These principles guided the first iteration of the drivetrain, and all further mechanical projects. It is not perfect but certainly meets our initial requirements, and was manufactured cheaply, quickly, and in discreet modules. The drivetrain is a differential drivetrain powered by two encoded DC gear motors driving the wheels with timing belts. (fig 1).

The drivetrain is simple enough conceptually, differential drives are one of the most basic configurations. The innovations in the drivetrain are mostly in the methods we used to manufacture, which paved the way for creating complicated, low cost designs on a tight time frame.